Supervisory apparatus for radio beacons



SUPERVISORY APPARATUS FOR RADIO BEACONS Filed Feb. 11 1932 fm em ars frnsf/framar Patented Apr. 3, 193% w en SUPERVKSORY 'AKPARATUS FOR RADIO EEACONS Ernst Kramer, Berlin-Tempelhof, Germany, assignor to C. Lorenz Aktiengesellschaft, Berlin- 'lcmpclhof, Germany 7 Application February 11, 1932, Serial No. 592,216

In Germany February 13, 1931 3 Claims.

In the operation of radio beacons, difficulty is met with in the control at the transmitting end or the radiations from the directional antenna systems. In most cases, these radiations are directed perpendicularly to one another, the supervision of the radiating conditions and tuning or" the transmitter arrangement so that the radiations from the two antenna systems are identical or, in certain circumstances, in a definite permanent relation, really necessitates taking a r ceiver into the field of radiation. This, however, oiiers the further difliculty that it is desired to supervise the transmission from the transmitting station itself. Therefore, it must suffice just to supervise the antenna circuits themselves. The ordinary use of antenna-ammeters, however, is unsatisfactory since different signals must be transmitted by the two antenna systems in order to produce a continuous dash in a receiver situated in the bisector of the angle between the two directions of radiation. Comparison of the readings of the two antenna-ammeters cannot be carried out since the emission of the signals takes place far too quickly.

According to the present invention, a supervisory arrangement for radio beacons transmitting complementary signals in a number of directions is provided, in which a pick up circuit, connected to indicating device, is located in a field derived from the energy employed for the transmission and resembling in form the field arising from the antenna or antenna.

An embodiment of the invention will now be described with reference to the accompanying drawing given by way of example. High-frequency energy is supplied through the coupling arrangement L1, L2, to the coil L2, to which are coupled two choke coils Drl and D'r2 which are connected to two different circuits each feeding a directional antenna system. The antennae are denoted by Al and A2. Both choke coils have keying windings d1, (t2 and in addition the choke coil Dr2 has a winding d acting in opposition to its k ying winding (22. The circuit arrangement shown in the drawing is such that the circuits supplying the high frequency energy to the antenna systems are alternately keyed by the coils Drl, Dr2 by means of the series-connected keying windings d1, d2. On closing the keying arrangement T, the coil Drl is magnetized whilst the coil D12 is de-magnetized, the winding (12 counteracting the winding d so as to neutralize the magnetizing action thereof. The arrangement as thus far described is fully disclosed in United States Patent No. 1,931,864.

For the purpose of the new invention there are inserted in the circuits of the antennae Al and A2, coupling arrangements L3 and L4 through which a small part of the antenna energy is supplied to the supervisory apparatus K. The two coupling arrangements are connected to two inductances L5 and L6 which may be perpendicular to one another. Within these two coils a third coil L7 is disposed, rotatably, in the manner of a goniometer arrangement. The two coupling coils and L5 are at right angles in this case, if also the directional antenna systems are at right angles to one another. If the two directional antenna systeu s enclose a different angle, however, the coupling coils of the supervisory apparatus are arranged to have the latter angle with one another. The inductance L7 represents herefore nothing more than a receiver having a frame antenna located in the field of the antenna Al and A2. It is therefore possible to control the conditions of the antenna circuits at this point satisfactorily, but not, of course, the conditions of reception at a great distance from the transmitter. However, since it may be assumed that the radiation conditions near a transmitter are constant, and any disturbing phenomena only become noticeable at a long distance, this supervision is quite suiiicient for practical requirements. A valve-voltmeter V in circuit with the valve R is connected to the inductance L7 in welllrnown manner.

The operation of the arrangement is as follows: On keying the antenna systems Al and A2, fields are produced in the coils L5 and L6. If the coupling coil L7 is at right-angles to L5 and L6 the valve-voltmeter must show a constant deflection, since the goniometer field is constant owing to the alternate keying of the two antenna systems.

As soon as the valve-voltmeter deviates from the constant deflection, this is a sign that the radiation is no longer identical in the two directions. Therefore, the antenna systems must be suitably re-tuned. By means of this arrangement perfect supervision is obtained. As soon as no uniform supply of energy from the transmitter to the antenna system takes place for any reason, the supervisory apparatus responds. It responds even to a variation in the antenna. circuit itself, if for instance one of the antenna is influenced by temperature influences, iceload or the like so that the tuning is altered.

It is apparent that since the operation of the arrangement according to the invention is independent of the keying arrangements or antenna systems, it must not be considered as applicable only to the described type of antenna systems or keying arrangements, but is applicable to any kind thereof.

What is claimed is:

1. In a supervisory apparatus for radio beacons with several antennae, a plurality of coils disposed in space relation corresponding to the directions of signal transmission, means coupling each of these coils to a definite one of the circuits of the said antennae, a pick up circuit located in the field produced by said coils, and an indicator coupled to said pick up circuit.

2. In a supervisory apparatus for radio beacons with antennae for transmitting in two-directions at right angles, two coils disposed at right angles one to the other, and one embracing the other, a third coil positioned within the other two coils,

an indicator, means coupling the third coil to said indicator, and means for coupling each of the two first mentioned coils to a definite one of the circuits of the said antennae.

3. In a supervisory apparatus for radio beacons with several antennae, a plurality of coils dis-- 

